Problem: Simplify the following expression: ${-2(-r+2)+4(-4-9r)}$
Explanation: Distribute the ${-2}$ into the first set of parentheses: $ {-2(}\gray{-r+2}{)} + 4(-4-9r) $ $ {2r-4} + 4(-4-9r) $ Distribute the ${4}$ into the parentheses: $ 2r-4 + {4(}\gray{-4-9r}{)} $ $ 2r-4 {-16-36r} $ Rewrite the expression to group the ${r}$ terms and numeric terms: $ {2r - 36r} {-4 - 16}$ Combine the ${r}$ terms: $ {-34r} {-4 - 16}$ Combine the numeric terms: $ {-34r} {-20}$ The simplified expression is $-34r-20$